In the press shop, stamping comes down to one simple idea: a press and a die apply force to sheet, strip, tube, or profile stock so the material either plastically deforms or separates into the shape and size we need. The old hands call it the "three essentials" — press, die, and material — and none of them can be missing. Get the press tonnage or die setup wrong, or run a material that doesn't match the process window, and you'll see it immediately in part quality and die life. For tooling engineers, this is also where die design starts: blanking and piercing dies are built around separation, while bending and drawing dies are built around controlled flow of the material.
Take a common 1.5mm cold-rolled steel sheet as an example. For blanking, the punch-to-die clearance is typically set at 8%–12% of material thickness, so roughly 0.12–0.18mm here. Go too tight and burr height climbs while die wear accelerates; go too loose and you get a pronounced rollover and a rough fracture surface. In practice, clearance is not a single number pulled from a table — it depends on material grade, thickness tolerance, and the edge quality the customer specifies. That's why die makers often fine-tune punch and die inserts after the first trial run rather than locking in dimensions from the drawing alone. Lubrication, die block material, and heat treatment of the cutting edges all affect how long that clearance stays in spec.
The basic operations — blanking, piercing, bending, and drawing — are easy to confuse when you're new, but the distinction matters: blanking and piercing are separation processes, while bending and drawing are forming processes. Knowing which one you're looking at tells you what to check first — burr and fracture zone for separation, springback and thinning for forming. For more mold sourcing information, visit MoldSo at www.moldso.com.